<span>The oesophagus is the muscular tube in humans and most other vertebrate organisms that carries food from the pharynx, or throat, down to the stomach. It is lined with a thick, moist pink tissue called mucosa.</span>
From this we can conclude that the human digestive system does not produce enzymes that can break down cellulose. The correct option among all the options that are given in the question is the fourth option or the last option. I hope that this is the answer that has come to your desired help.